<!DOCTYPE html>
<html lang="en" ng-app="app01">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../lib/angularjs/angular1.6.3.min.js"></script>
</head>
<body>
    <div ng-controller="myController">
        <input type="text" ng-model="expr">
        {{newNumber}}
        <script>
            var app=angular.module("app01",[]);
            app.controller("myController",function ($scope,$parse) {
                $scope.newNumber="";
                $scope.$watch('expr', function(newVal, oldVal, scope) {
                    scope.newNumber=newVal+"-->"+oldVal+"-->"+$parse(newVal);
                });
            });
        </script>
    </div>
</body>
</html>